cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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head_32.S (14100B)


      1/* SPDX-License-Identifier: GPL-2.0 */
      2/*
      3 *
      4 *  Copyright (C) 1991, 1992  Linus Torvalds
      5 *
      6 *  Enhanced CPU detection and feature setting code by Mike Jagdis
      7 *  and Martin Mares, November 1997.
      8 */
      9
     10.text
     11#include <linux/threads.h>
     12#include <linux/init.h>
     13#include <linux/linkage.h>
     14#include <asm/segment.h>
     15#include <asm/page_types.h>
     16#include <asm/pgtable_types.h>
     17#include <asm/cache.h>
     18#include <asm/thread_info.h>
     19#include <asm/asm-offsets.h>
     20#include <asm/setup.h>
     21#include <asm/processor-flags.h>
     22#include <asm/msr-index.h>
     23#include <asm/cpufeatures.h>
     24#include <asm/percpu.h>
     25#include <asm/nops.h>
     26#include <asm/bootparam.h>
     27#include <asm/export.h>
     28#include <asm/pgtable_32.h>
     29
     30/* Physical address */
     31#define pa(X) ((X) - __PAGE_OFFSET)
     32
     33/*
     34 * References to members of the new_cpu_data structure.
     35 */
     36
     37#define X86		new_cpu_data+CPUINFO_x86
     38#define X86_VENDOR	new_cpu_data+CPUINFO_x86_vendor
     39#define X86_MODEL	new_cpu_data+CPUINFO_x86_model
     40#define X86_STEPPING	new_cpu_data+CPUINFO_x86_stepping
     41#define X86_HARD_MATH	new_cpu_data+CPUINFO_hard_math
     42#define X86_CPUID	new_cpu_data+CPUINFO_cpuid_level
     43#define X86_CAPABILITY	new_cpu_data+CPUINFO_x86_capability
     44#define X86_VENDOR_ID	new_cpu_data+CPUINFO_x86_vendor_id
     45
     46
     47#define SIZEOF_PTREGS 17*4
     48
     49/*
     50 * Worst-case size of the kernel mapping we need to make:
     51 * a relocatable kernel can live anywhere in lowmem, so we need to be able
     52 * to map all of lowmem.
     53 */
     54KERNEL_PAGES = LOWMEM_PAGES
     55
     56INIT_MAP_SIZE = PAGE_TABLE_SIZE(KERNEL_PAGES) * PAGE_SIZE
     57RESERVE_BRK(pagetables, INIT_MAP_SIZE)
     58
     59/*
     60 * 32-bit kernel entrypoint; only used by the boot CPU.  On entry,
     61 * %esi points to the real-mode code as a 32-bit pointer.
     62 * CS and DS must be 4 GB flat segments, but we don't depend on
     63 * any particular GDT layout, because we load our own as soon as we
     64 * can.
     65 */
     66__HEAD
     67SYM_CODE_START(startup_32)
     68	movl pa(initial_stack),%ecx
     69	
     70/*
     71 * Set segments to known values.
     72 */
     73	lgdt pa(boot_gdt_descr)
     74	movl $(__BOOT_DS),%eax
     75	movl %eax,%ds
     76	movl %eax,%es
     77	movl %eax,%fs
     78	movl %eax,%gs
     79	movl %eax,%ss
     80	leal -__PAGE_OFFSET(%ecx),%esp
     81
     82/*
     83 * Clear BSS first so that there are no surprises...
     84 */
     85	cld
     86	xorl %eax,%eax
     87	movl $pa(__bss_start),%edi
     88	movl $pa(__bss_stop),%ecx
     89	subl %edi,%ecx
     90	shrl $2,%ecx
     91	rep ; stosl
     92/*
     93 * Copy bootup parameters out of the way.
     94 * Note: %esi still has the pointer to the real-mode data.
     95 * With the kexec as boot loader, parameter segment might be loaded beyond
     96 * kernel image and might not even be addressable by early boot page tables.
     97 * (kexec on panic case). Hence copy out the parameters before initializing
     98 * page tables.
     99 */
    100	movl $pa(boot_params),%edi
    101	movl $(PARAM_SIZE/4),%ecx
    102	cld
    103	rep
    104	movsl
    105	movl pa(boot_params) + NEW_CL_POINTER,%esi
    106	andl %esi,%esi
    107	jz 1f			# No command line
    108	movl $pa(boot_command_line),%edi
    109	movl $(COMMAND_LINE_SIZE/4),%ecx
    110	rep
    111	movsl
    1121:
    113
    114#ifdef CONFIG_OLPC
    115	/* save OFW's pgdir table for later use when calling into OFW */
    116	movl %cr3, %eax
    117	movl %eax, pa(olpc_ofw_pgd)
    118#endif
    119
    120#ifdef CONFIG_MICROCODE
    121	/* Early load ucode on BSP. */
    122	call load_ucode_bsp
    123#endif
    124
    125	/* Create early pagetables. */
    126	call  mk_early_pgtbl_32
    127
    128	/* Do early initialization of the fixmap area */
    129	movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
    130#ifdef  CONFIG_X86_PAE
    131#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
    132	movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8)
    133#else
    134	movl %eax,pa(initial_page_table+0xffc)
    135#endif
    136
    137	jmp .Ldefault_entry
    138SYM_CODE_END(startup_32)
    139
    140#ifdef CONFIG_HOTPLUG_CPU
    141/*
    142 * Boot CPU0 entry point. It's called from play_dead(). Everything has been set
    143 * up already except stack. We just set up stack here. Then call
    144 * start_secondary().
    145 */
    146SYM_FUNC_START(start_cpu0)
    147	movl initial_stack, %ecx
    148	movl %ecx, %esp
    149	call *(initial_code)
    1501:	jmp 1b
    151SYM_FUNC_END(start_cpu0)
    152#endif
    153
    154/*
    155 * Non-boot CPU entry point; entered from trampoline.S
    156 * We can't lgdt here, because lgdt itself uses a data segment, but
    157 * we know the trampoline has already loaded the boot_gdt for us.
    158 *
    159 * If cpu hotplug is not supported then this code can go in init section
    160 * which will be freed later
    161 */
    162SYM_FUNC_START(startup_32_smp)
    163	cld
    164	movl $(__BOOT_DS),%eax
    165	movl %eax,%ds
    166	movl %eax,%es
    167	movl %eax,%fs
    168	movl %eax,%gs
    169	movl pa(initial_stack),%ecx
    170	movl %eax,%ss
    171	leal -__PAGE_OFFSET(%ecx),%esp
    172
    173#ifdef CONFIG_MICROCODE
    174	/* Early load ucode on AP. */
    175	call load_ucode_ap
    176#endif
    177
    178.Ldefault_entry:
    179	movl $(CR0_STATE & ~X86_CR0_PG),%eax
    180	movl %eax,%cr0
    181
    182/*
    183 * We want to start out with EFLAGS unambiguously cleared. Some BIOSes leave
    184 * bits like NT set. This would confuse the debugger if this code is traced. So
    185 * initialize them properly now before switching to protected mode. That means
    186 * DF in particular (even though we have cleared it earlier after copying the
    187 * command line) because GCC expects it.
    188 */
    189	pushl $0
    190	popfl
    191
    192/*
    193 * New page tables may be in 4Mbyte page mode and may be using the global pages.
    194 *
    195 * NOTE! If we are on a 486 we may have no cr4 at all! Specifically, cr4 exists
    196 * if and only if CPUID exists and has flags other than the FPU flag set.
    197 */
    198	movl $-1,pa(X86_CPUID)		# preset CPUID level
    199	movl $X86_EFLAGS_ID,%ecx
    200	pushl %ecx
    201	popfl				# set EFLAGS=ID
    202	pushfl
    203	popl %eax			# get EFLAGS
    204	testl $X86_EFLAGS_ID,%eax	# did EFLAGS.ID remained set?
    205	jz .Lenable_paging		# hw disallowed setting of ID bit
    206					# which means no CPUID and no CR4
    207
    208	xorl %eax,%eax
    209	cpuid
    210	movl %eax,pa(X86_CPUID)		# save largest std CPUID function
    211
    212	movl $1,%eax
    213	cpuid
    214	andl $~1,%edx			# Ignore CPUID.FPU
    215	jz .Lenable_paging		# No flags or only CPUID.FPU = no CR4
    216
    217	movl pa(mmu_cr4_features),%eax
    218	movl %eax,%cr4
    219
    220	testb $X86_CR4_PAE, %al		# check if PAE is enabled
    221	jz .Lenable_paging
    222
    223	/* Check if extended functions are implemented */
    224	movl $0x80000000, %eax
    225	cpuid
    226	/* Value must be in the range 0x80000001 to 0x8000ffff */
    227	subl $0x80000001, %eax
    228	cmpl $(0x8000ffff-0x80000001), %eax
    229	ja .Lenable_paging
    230
    231	/* Clear bogus XD_DISABLE bits */
    232	call verify_cpu
    233
    234	mov $0x80000001, %eax
    235	cpuid
    236	/* Execute Disable bit supported? */
    237	btl $(X86_FEATURE_NX & 31), %edx
    238	jnc .Lenable_paging
    239
    240	/* Setup EFER (Extended Feature Enable Register) */
    241	movl $MSR_EFER, %ecx
    242	rdmsr
    243
    244	btsl $_EFER_NX, %eax
    245	/* Make changes effective */
    246	wrmsr
    247
    248.Lenable_paging:
    249
    250/*
    251 * Enable paging
    252 */
    253	movl $pa(initial_page_table), %eax
    254	movl %eax,%cr3		/* set the page table pointer.. */
    255	movl $CR0_STATE,%eax
    256	movl %eax,%cr0		/* ..and set paging (PG) bit */
    257	ljmp $__BOOT_CS,$1f	/* Clear prefetch and normalize %eip */
    2581:
    259	/* Shift the stack pointer to a virtual address */
    260	addl $__PAGE_OFFSET, %esp
    261
    262/*
    263 * start system 32-bit setup. We need to re-do some of the things done
    264 * in 16-bit mode for the "real" operations.
    265 */
    266	movl setup_once_ref,%eax
    267	andl %eax,%eax
    268	jz 1f				# Did we do this already?
    269	call *%eax
    2701:
    271
    272/*
    273 * Check if it is 486
    274 */
    275	movb $4,X86			# at least 486
    276	cmpl $-1,X86_CPUID
    277	je .Lis486
    278
    279	/* get vendor info */
    280	xorl %eax,%eax			# call CPUID with 0 -> return vendor ID
    281	cpuid
    282	movl %eax,X86_CPUID		# save CPUID level
    283	movl %ebx,X86_VENDOR_ID		# lo 4 chars
    284	movl %edx,X86_VENDOR_ID+4	# next 4 chars
    285	movl %ecx,X86_VENDOR_ID+8	# last 4 chars
    286
    287	orl %eax,%eax			# do we have processor info as well?
    288	je .Lis486
    289
    290	movl $1,%eax		# Use the CPUID instruction to get CPU type
    291	cpuid
    292	movb %al,%cl		# save reg for future use
    293	andb $0x0f,%ah		# mask processor family
    294	movb %ah,X86
    295	andb $0xf0,%al		# mask model
    296	shrb $4,%al
    297	movb %al,X86_MODEL
    298	andb $0x0f,%cl		# mask mask revision
    299	movb %cl,X86_STEPPING
    300	movl %edx,X86_CAPABILITY
    301
    302.Lis486:
    303	movl $0x50022,%ecx	# set AM, WP, NE and MP
    304	movl %cr0,%eax
    305	andl $0x80000011,%eax	# Save PG,PE,ET
    306	orl %ecx,%eax
    307	movl %eax,%cr0
    308
    309	lgdt early_gdt_descr
    310	ljmp $(__KERNEL_CS),$1f
    3111:	movl $(__KERNEL_DS),%eax	# reload all the segment registers
    312	movl %eax,%ss			# after changing gdt.
    313
    314	movl $(__USER_DS),%eax		# DS/ES contains default USER segment
    315	movl %eax,%ds
    316	movl %eax,%es
    317
    318	movl $(__KERNEL_PERCPU), %eax
    319	movl %eax,%fs			# set this cpu's percpu
    320
    321	xorl %eax,%eax
    322	movl %eax,%gs			# clear possible garbage in %gs
    323
    324	xorl %eax,%eax			# Clear LDT
    325	lldt %ax
    326
    327	call *(initial_code)
    3281:	jmp 1b
    329SYM_FUNC_END(startup_32_smp)
    330
    331#include "verify_cpu.S"
    332
    333/*
    334 *  setup_once
    335 *
    336 *  The setup work we only want to run on the BSP.
    337 *
    338 *  Warning: %esi is live across this function.
    339 */
    340__INIT
    341setup_once:
    342	andl $0,setup_once_ref	/* Once is enough, thanks */
    343	RET
    344
    345SYM_FUNC_START(early_idt_handler_array)
    346	# 36(%esp) %eflags
    347	# 32(%esp) %cs
    348	# 28(%esp) %eip
    349	# 24(%rsp) error code
    350	i = 0
    351	.rept NUM_EXCEPTION_VECTORS
    352	.if ((EXCEPTION_ERRCODE_MASK >> i) & 1) == 0
    353	pushl $0		# Dummy error code, to make stack frame uniform
    354	.endif
    355	pushl $i		# 20(%esp) Vector number
    356	jmp early_idt_handler_common
    357	i = i + 1
    358	.fill early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
    359	.endr
    360SYM_FUNC_END(early_idt_handler_array)
    361	
    362SYM_CODE_START_LOCAL(early_idt_handler_common)
    363	/*
    364	 * The stack is the hardware frame, an error code or zero, and the
    365	 * vector number.
    366	 */
    367	cld
    368
    369	incl %ss:early_recursion_flag
    370
    371	/* The vector number is in pt_regs->gs */
    372
    373	cld
    374	pushl	%fs		/* pt_regs->fs (__fsh varies by model) */
    375	pushl	%es		/* pt_regs->es (__esh varies by model) */
    376	pushl	%ds		/* pt_regs->ds (__dsh varies by model) */
    377	pushl	%eax		/* pt_regs->ax */
    378	pushl	%ebp		/* pt_regs->bp */
    379	pushl	%edi		/* pt_regs->di */
    380	pushl	%esi		/* pt_regs->si */
    381	pushl	%edx		/* pt_regs->dx */
    382	pushl	%ecx		/* pt_regs->cx */
    383	pushl	%ebx		/* pt_regs->bx */
    384
    385	/* Fix up DS and ES */
    386	movl	$(__KERNEL_DS), %ecx
    387	movl	%ecx, %ds
    388	movl	%ecx, %es
    389
    390	/* Load the vector number into EDX */
    391	movl	PT_GS(%esp), %edx
    392
    393	/* Load GS into pt_regs->gs (and maybe clobber __gsh) */
    394	movw	%gs, PT_GS(%esp)
    395
    396	movl	%esp, %eax	/* args are pt_regs (EAX), trapnr (EDX) */
    397	call	early_fixup_exception
    398
    399	popl	%ebx		/* pt_regs->bx */
    400	popl	%ecx		/* pt_regs->cx */
    401	popl	%edx		/* pt_regs->dx */
    402	popl	%esi		/* pt_regs->si */
    403	popl	%edi		/* pt_regs->di */
    404	popl	%ebp		/* pt_regs->bp */
    405	popl	%eax		/* pt_regs->ax */
    406	popl	%ds		/* pt_regs->ds (always ignores __dsh) */
    407	popl	%es		/* pt_regs->es (always ignores __esh) */
    408	popl	%fs		/* pt_regs->fs (always ignores __fsh) */
    409	popl	%gs		/* pt_regs->gs (always ignores __gsh) */
    410	decl	%ss:early_recursion_flag
    411	addl	$4, %esp	/* pop pt_regs->orig_ax */
    412	iret
    413SYM_CODE_END(early_idt_handler_common)
    414
    415/* This is the default interrupt "handler" :-) */
    416SYM_FUNC_START(early_ignore_irq)
    417	cld
    418#ifdef CONFIG_PRINTK
    419	pushl %eax
    420	pushl %ecx
    421	pushl %edx
    422	pushl %es
    423	pushl %ds
    424	movl $(__KERNEL_DS),%eax
    425	movl %eax,%ds
    426	movl %eax,%es
    427	cmpl $2,early_recursion_flag
    428	je hlt_loop
    429	incl early_recursion_flag
    430	pushl 16(%esp)
    431	pushl 24(%esp)
    432	pushl 32(%esp)
    433	pushl 40(%esp)
    434	pushl $int_msg
    435	call _printk
    436
    437	call dump_stack
    438
    439	addl $(5*4),%esp
    440	popl %ds
    441	popl %es
    442	popl %edx
    443	popl %ecx
    444	popl %eax
    445#endif
    446	iret
    447
    448hlt_loop:
    449	hlt
    450	jmp hlt_loop
    451SYM_FUNC_END(early_ignore_irq)
    452
    453__INITDATA
    454	.align 4
    455SYM_DATA(early_recursion_flag, .long 0)
    456
    457__REFDATA
    458	.align 4
    459SYM_DATA(initial_code,		.long i386_start_kernel)
    460SYM_DATA(setup_once_ref,	.long setup_once)
    461
    462#ifdef CONFIG_PAGE_TABLE_ISOLATION
    463#define	PGD_ALIGN	(2 * PAGE_SIZE)
    464#define PTI_USER_PGD_FILL	1024
    465#else
    466#define	PGD_ALIGN	(PAGE_SIZE)
    467#define PTI_USER_PGD_FILL	0
    468#endif
    469/*
    470 * BSS section
    471 */
    472__PAGE_ALIGNED_BSS
    473	.align PGD_ALIGN
    474#ifdef CONFIG_X86_PAE
    475.globl initial_pg_pmd
    476initial_pg_pmd:
    477	.fill 1024*KPMDS,4,0
    478#else
    479.globl initial_page_table
    480initial_page_table:
    481	.fill 1024,4,0
    482#endif
    483	.align PGD_ALIGN
    484initial_pg_fixmap:
    485	.fill 1024,4,0
    486.globl swapper_pg_dir
    487	.align PGD_ALIGN
    488swapper_pg_dir:
    489	.fill 1024,4,0
    490	.fill PTI_USER_PGD_FILL,4,0
    491.globl empty_zero_page
    492empty_zero_page:
    493	.fill 4096,1,0
    494EXPORT_SYMBOL(empty_zero_page)
    495
    496/*
    497 * This starts the data section.
    498 */
    499#ifdef CONFIG_X86_PAE
    500__PAGE_ALIGNED_DATA
    501	/* Page-aligned for the benefit of paravirt? */
    502	.align PGD_ALIGN
    503SYM_DATA_START(initial_page_table)
    504	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR),0	/* low identity map */
    505# if KPMDS == 3
    506	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR),0
    507	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0
    508	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR+0x2000),0
    509# elif KPMDS == 2
    510	.long	0,0
    511	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR),0
    512	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0
    513# elif KPMDS == 1
    514	.long	0,0
    515	.long	0,0
    516	.long	pa(initial_pg_pmd+PGD_IDENT_ATTR),0
    517# else
    518#  error "Kernel PMDs should be 1, 2 or 3"
    519# endif
    520	.align PAGE_SIZE		/* needs to be page-sized too */
    521
    522#ifdef CONFIG_PAGE_TABLE_ISOLATION
    523	/*
    524	 * PTI needs another page so sync_initial_pagetable() works correctly
    525	 * and does not scribble over the data which is placed behind the
    526	 * actual initial_page_table. See clone_pgd_range().
    527	 */
    528	.fill 1024, 4, 0
    529#endif
    530
    531SYM_DATA_END(initial_page_table)
    532#endif
    533
    534.data
    535.balign 4
    536/*
    537 * The SIZEOF_PTREGS gap is a convention which helps the in-kernel unwinder
    538 * reliably detect the end of the stack.
    539 */
    540SYM_DATA(initial_stack,
    541		.long init_thread_union + THREAD_SIZE -
    542		SIZEOF_PTREGS - TOP_OF_KERNEL_STACK_PADDING)
    543
    544__INITRODATA
    545int_msg:
    546	.asciz "Unknown interrupt or fault at: %p %p %p\n"
    547
    548#include "../../x86/xen/xen-head.S"
    549
    550/*
    551 * The IDT and GDT 'descriptors' are a strange 48-bit object
    552 * only used by the lidt and lgdt instructions. They are not
    553 * like usual segment descriptors - they consist of a 16-bit
    554 * segment size, and 32-bit linear address value:
    555 */
    556
    557	.data
    558	ALIGN
    559# early boot GDT descriptor (must use 1:1 address mapping)
    560	.word 0				# 32 bit align gdt_desc.address
    561SYM_DATA_START_LOCAL(boot_gdt_descr)
    562	.word __BOOT_DS+7
    563	.long boot_gdt - __PAGE_OFFSET
    564SYM_DATA_END(boot_gdt_descr)
    565
    566# boot GDT descriptor (later on used by CPU#0):
    567	.word 0				# 32 bit align gdt_desc.address
    568SYM_DATA_START(early_gdt_descr)
    569	.word GDT_ENTRIES*8-1
    570	.long gdt_page			/* Overwritten for secondary CPUs */
    571SYM_DATA_END(early_gdt_descr)
    572
    573/*
    574 * The boot_gdt must mirror the equivalent in setup.S and is
    575 * used only for booting.
    576 */
    577	.align L1_CACHE_BYTES
    578SYM_DATA_START(boot_gdt)
    579	.fill GDT_ENTRY_BOOT_CS,8,0
    580	.quad 0x00cf9a000000ffff	/* kernel 4GB code at 0x00000000 */
    581	.quad 0x00cf92000000ffff	/* kernel 4GB data at 0x00000000 */
    582SYM_DATA_END(boot_gdt)